1. Field of the Invention
The invention relates to tamper evident seals of the type used to provide visual evidence of unauthorized access to and/or tampering with locks and other like security devices. The invention is especially useful for, although not limited to, maintaining the security of meters employed by utility companies to monitor customers' energy consumption.
2. Description of the Prior Art
Conventionally, tamper evident seals for use with security devices include a slender flexible element, typically a metallic wire, formed into a half loop having two interconnected arms. One arm is threaded through aligned apertures in the interlocked components to be safeguarded against tampering, and portions of both arms are then captured within a seal body.
In an earlier seal version, the seal body is formed of a malleable metal, typically lead. The body is crimped onto the two wire arms by a special tool designed to leave a visually distinctive permanent impression. In theory, any attempt to dislodge the seal body from the wire will result in the crimped impression being altered, thereby providing visual evidence of tampering. In practice, however, tampering remains possible, typically by heating the seal body sufficiently to soften the metal without altering its exterior appearance, thereby permitting the wire to be extricated and reinserted without visibly altering the overall appearance of the seal.
Such seals are also designed to be used once and then discarded. Improper disposal of lead seal bodies raises health and environmental concerns, particularly in crowded urban areas where frequent access to utility meters by maintenance personnel is required.
Attempts have been made at dealing with the above described problems by developing new seals wherein the flexible elements and seal bodies are integrally formed of non metallic materials, typically as injection molded plastic components. While this approach does respond to health concerns and certain environmental concerns, it does little to correct the tampering problem because the all plastic components are still susceptible to being heat softened to permit disconnection and reassembly without leaving observable traces of tampering.
A further attempt at providing an improved seal involves the combination of a metallic wire with a plastic body having inner and outer mutually adjustable components designed to grip arms of the wire threaded therethrough. Here again, however, heat softening of the plastic components can compromise seal integrity. Moreover, application of the seal body to the wire of certain seals requires the use of an expensive specially designed tool, which further increases overall costs while also unnecessarily burdening maintenance personnel.
A general object of the present invention is to provide a tamper evident seal which either obviates or at least significantly minimizes the above described problems associated with known prior art devices.
A more specific object of the present invention is the provision of a tamper evident seal having features which preclude tampering without residual visual evidence.
Another object of the present invention is the provision of a tamper evident seal that can be installed quickly and efficiently by maintenance personnel without the need to resort to the use of expensive specially designed tools.